1. Field of the Invention
The present invention relates to an image processing apparatus for and an image processing method of subjecting image data, which is obtained from an image recorded through a photographing lens of a camera, to predetermined image processing to thereby arrange the resultant image data as output image data, and more particularly, to an image processing apparatus for and an image processing method of improving the quality of an image by applying a decreased marginal illumination quantity correction to the light whose quantity is decreased in the marginal portion of an image, which is caused when the image is recorded with a less expensive lens such as a film with a lens.
2. Related Background Art
Most of the images recorded on photographic films such as negatives and reversals (which are hereinafter referred to as “films”) are conventionally printed onto light-sensitive materials (photographic papers) by a technique generally called “direct exposure” (analog exposure, areal exposure) in which the image on a film is projected onto the light-sensitive material for areal exposure (one spot exposure).
In contrast, recently, a printer which adopts digital exposure, that is, a digital photoprinter has recently been commercialized. In this “digital photoprinter”, the image recorded on a film is read photoelectrically; the resultant image is converted into digital signals, which are subjected to various kinds of image processing and arranged as recording image data; and a light-sensitive material is scan exposed with recording light modulated according to the image data to thereby record an image (latent image) on the light-sensitive material; and a (finished) print, on which the image is reproduced, is produced.
According to the digital photoprinter, exposing conditions used in printing can be determined by subjecting an image to image data processing as digital image data. Thus, a print of high quality, which cannot be obtained by conventional direct exposure, can be obtained by appropriately subjecting the image data to a correction of washed-out highlight and dull-shadow of the image, which are caused when the image is recorded in backlight or with an electronic flash, to sharpness processing, and to a color and density failure correction, and the like. Further, the digital photoprinter can combine a plurality of images to a composite image, can divide a single image into segments, can combine characters to a composite character, and also can output a print that is freely edited and processed depending on a specific use.
Moreover, the digital photoprinter can not only output an image as a print but also supply image data to a computer, and the like and store it in a recording medium such as a floppy, and the like, whereby the image data can be used in various applications other than a photograph.
The digital photoprinter like this basically includes an image input apparatus that has a scanner (image reading apparatus) and an image processing apparatus, and an image output apparatus that has a printer (image recording apparatus) and a processor (development apparatus). The scanner photoelectrically reads the image recorded on a film; the image processing apparatus subjects the thus read image to image processing and arranges it as output image data (exposing conditions); the printer scan exposes a light-sensitive material according to image data output from the image input apparatus and records a latent image on the light-sensitive material; and the processor develops the thus exposed light-sensitive material and arranges it as a print.
The scanner supplies the reading light emitted from a light source to the film and obtains projecting light carrying the image recorded on the film, reads the image by imaging the projecting light on an image sensor such as a CCD sensor through an imaging lens and by photoelectrically converting the projecting light. Thereafter, the image is subjected to various kinds of processing, when necessary, and is supplied to the image processing apparatus as the image data (image data signals) of the film.
The image processing apparatus sets image processing conditions from the image data read with the scanner, subjects the image data to image processing according to the thus set conditions, and supplies the resultant image data to the printer as output image data (exposing conditions) for recording the image.
When the printer is an apparatus making use of, for example, scan exposure performed with a light beam, it modulates the light beam according to the image data supplied from the image processing apparatus, deflects the light beam in a main scan direction as well as transports the light-sensitive material in a sub-scan direction perpendicular to the main scan direction, thereby the latent image is formed on the light-sensitive material by exposing (printing) it with the light beam carrying the image. Then, the processor subjects the latent image to development processing, and the like according to the light-sensitive material so as to arrange the light-sensitive material as a print (photograph) on which the image recorded on the film is reproduced.
Incidentally, the quality of the image reproduced on the print is deteriorated by the reduction of marginal illumination (decreased quantity of marginal illumination), which is caused by the performance of a lens mounted on a camera, and lens aberrations such as magnification chromatic aberration, and distortion.
In particular, a lens-fitted photographic film package, a less expensive compact camera, and the like employ so-called single- and two-element lenses to reduce a lens cost to cope with the restriction in cost.
As a result, in the lens-fitted photographic film package and the less expensive compact camera, the quantity of light incident on a recording plane is reduced from the center of a lens toward the marginal portion thereof, which causes so-called marginal illumination reduction by which an image is made dark.
At this time, the phenomenon that the image is made dark in the marginal portion appears on a print as it is in a conventional areal exposure printer, from which a problem arises in that the quality of the image on the print is deteriorated.
In contrast, while various attempts have been made to improve the quality of the image on a print by subjecting image data arranged as digital signals to digital image processing by the digital photoprinter, there is a room for more improving the quality of the image on the print.